Yesterday, Justice Minister Amy Adams and Police Minister Michael Woodhouse announced the new information-sharing agreement had been signed.
It comes after a commitment in February between Mr Key and the then Australian Prime Minister Tony Abbott to share more information.
Mr Woodhouse and Ms Adams said that while concerns about the scope of Australia's deportation policy remained, the agreement would enable authorities here to assess the risk of those deported to New Zealand.
"This arrangement will provide New Zealand agencies with up to six months' advance notice of potential upcoming deportations, and provide for the sharing of information prior to arrival that will help New Zealand better manage the return of New Zealand citizens such as criminal conviction records, summary of offences, case history, gang connections, fingerprints and photographs," Mr Woodhouse said.
"It's a significant improvement on what Australia has been able to provide New Zealand and gives police the information they need to make more-informed assessments about the risks posed by deported offenders."
Ms Adams said now the information-sharing arrangement was agreed, a law change could be made to ensure offenders who arrive here were subject to the same oversight as they would have been if they served their prison sentence in NZ.